nextjsnext >=15.0.0runtime: nodejs

Next.js 15+ Asynchronous Request APIs (headers, cookies, params, searchParams)

Canonical Error Signature (SHA-256: 1743470a7dfb4311...)

Error: Route /api/stripe/webhook used "headers()" without await. `headers()`, `cookies()`, and `params` are now asynchronous in Next.js 15+

Verification Provenance

118 Docker exit-0 runs

Expected Token Arbitrage

~14,500 retry tokens saved

Pay-on-Proof Unlock

$0.005 Base USDC / 1 Credit

Machine Unlock Instructions (MCP & HTTP 402)

Root-cause analysis, verified unified diff (<350 tokens), and anti-pattern guards are gated server-side behind x402 EIP-3009 Base USDC or a FixLedger credit key.

# Option A: Streamable HTTP MCP tool call (https://fixledger-iota.vercel.app/api/mcp)
{
  "name": "unlock_verified_fix",
  "arguments": {
    "resolution_id": "nextjs-15-async-headers-cookies-params"
  }
}

# Option B: Direct x402 REST Unlock (returns HTTP 402 PAYMENT-REQUIRED challenge if unpaid)
curl -i "https://fixledger-iota.vercel.app/api/x402/unlock?id=nextjs-15-async-headers-cookies-params"